|
Post by fivendime on May 20, 2010 16:16:24 GMT -8
As so we dont get off track here, I will start another thread so you can put your options for bridge construction and material type etc. Meanwhile lets keep this to a simple width and weight question and answer.
The thread is in the "Yacolt Burn Trail Project" section titled What kind of Bridge to Use?
|
|
|
Post by ljdude on May 20, 2010 19:50:00 GMT -8
My long range expectation for 4x4 vehicles in the future: most vehicles are now at their maximum weights & we will see a decrease in weight into the future. Fuel economy/ green house gas emissions/ better performance with lighter weights will drive this weight reduction. Widths will continue to increase due to safety & performance gains for most types of motorized recreational users. This width increase is also evident in many cars/ light trucks of the last decade. Most vehicles get wider / longer over the model generation changes. Toyrocs I'm going to have to agree with you that future vehicles will be getting wider. I think that the bridge should be at least 102" in width. My Jeep LJ is 78" tire to tire so I can get by on a narrower bridge but what about the guy with an old Chevy or Ford. The trails should be where the challenges are at. Not the bridge!
|
|
beatcj
Ok to Drive
Flat out LAZY...
Posts: 169
|
Post by beatcj on May 22, 2010 12:56:23 GMT -8
I went out and measured the width of the duals on our F-550 Brush Truck, it was one of the trucks up at Jackson Pass last fall.
As it sits, the rear wheels are 94.5" bulge to bulge, and it's 14,500 or so, plus crew. Currently, the F-450/550 is the standard for Emergency Services in Clark County, and I know there is one that weighs 18,000 loaded.
Frankly, the only time I would expect to see us even think about using a trail is if we were accessing a patient or dealing with a vehicle fire. In my mind, it would be very poor tactics to put one of our trucks in there to deal with a wildland fire, the chances of escaping if things went poorly are somewhere between slim and none.
DNR tries to limit their wildland fire trucks to under 26,000 lbs, so their operators don't have to get CDLs. My understanding is that they are looking at the Chevy/GM TopKick crew cab as their standard for the future, so I suspect someone could get a width from that.
I doubt they would take those rigs across the bridge, most likely they would find a point on a road and walk in, too.
I will poll the responsible parties at the 5 agencies that are most likely to respond, and see if they want any additional input, but I would suspect that they would not plan on being a bridge user.
|
|
|
Post by Waderod1 on May 23, 2010 5:39:35 GMT -8
I think 9 foot wide would work. It might be a little tight for the bigger rigs, but it would be fine. I got a buggy with toyota running gear so im pretty narrow. Hopefully I will be able to make it to one of your pied piper meetings. Thanks for all your guys hard work and making it possible to wheel close to home. thank you. If theres anything I can do to help with trail work give me a call. Wade Lapp 360 608 1336
|
|
|
Post by Chip Still on May 24, 2010 17:37:34 GMT -8
I think toyroc has some very good ideas and I agree with the width. Overkill for most but big trucks will tear up anything smaller. Ya know their going to try to get across. I kinda like the underwater idea!
|
|
|
Post by bchutchens on Jun 4, 2010 10:43:17 GMT -8
|
|
|
Post by pistonschick on Jun 4, 2010 11:36:22 GMT -8
Some information I have recently received from DNR:
A fiberglass bridge at 102" wide and 85 feet in length can only be built to provide a 12,000 lb weight capacity - not enough to cover the "knuckle-head factor" on an 85 foot bridge.
The area that the bridge is going into is surrounded by "expensive" timber so using a helicopter to drop in a bridge will not be an option due to the cost that would be incurred to purchase the timber in order to have it removed.
Building a road into where the bridge is going in order to transport the bridge to the site would be well over a mile long and tree removal and road building costs would also be very high.
Not to mention that both options above would drastically impact the "look & feel" of the trail design that we are hoping for...
On that note, we are looking at an optional area for the water crossing which would consist of 2 or 3 much shorter bridge crossings. Shorter fiberglass bridges will provide for more weight capacity.
I will follow up later when I have more information...
Some thoughts from me (Crystal):
1) There will NEVER be an expectation or need for emergency vehicles to be travelling on the motorized trails - so we can probably stop using that analogy to support the construction of a "modern marvels" bridge to accommodate a truck-a-saurus-rex. We have to draw the line somewhere or we might as well get out the road graders and just build roads.
2) We are looking really hard at 102" right now as a recommendation to DNR for the inside bridge width - that's not etched in stone, just the number we are using to draw a bead on weight capacities for various bridge designs...
3) Also, ALL motorized trails in the Yacolt Burn will follow the existing seasonal closure which means that NO-ONE will be on the trails between December 1st thru April 30th. Since it is VERY unlikely that there will be snow on the trails when they are open, the bridge does not need to accommodate "extra-wide snow tires".
Please keep the ideas coming...
Crystal
|
|
|
Post by bchutchens on Jun 4, 2010 11:36:41 GMT -8
|
|
|
Post by joshwho on Jun 8, 2010 13:09:40 GMT -8
...I would safely assume that if it were a serious issue DNR would mandate that we have it that wide. x2. I think they're going to do what they need to do for emergency vehicles if they will indeed need access which will effectively render our opinions unnecessary. Crystal, you're right. The real question should be what is the width of the vehicles, not how wide should the bridge be. Without knowing the exact design and how much usable surface area there will be, the bridge's width is irrelevant. fwiw, 104" would cover Hummers as well. If I were building it, that's what I'd go with. Having a great relationship with the DNR is a good thing, and it won't take many instances of some yahoo in a Hummer not fitting and deciding to bypass it, tearing up 85 feet of protected watershed or wetlands, to create some bad vibes. (I posted this in the turning radius thread before I saw this one, but I think it fits, so I'll post it here) THIS IS MY BIGGEST CONCERN! people will travel to the trail system, wheel it and if they get halfway down a trail and are width limited they WILL quite often bypass someway and prob tear up what we're trying to protect by having the trail system. Just because we understand and respect the tread lightly idea of things, it doesn't mean everyone does (and I can GUARANTEE that pleanty of people just don't care), there are more and more people out there that start "wheeling" every day (some because they LOVE nature, some because they caught the bug and LOVE wheeling, but I KNOW there are tons that don't really care about either any of the good reasons and it's just a fad to them and they're trying to be "hardcore" (or whatever) and they really aren't interested in keeping it all around by respecting what we have and are given because they will "outgrow" it or just get tired with it when they find out that being in it for the long run isn't what they think it is. So in short I think filters would limit unnecessary trail damage, but that's kinda for a different thread I guess
|
|
|
Post by joshwho on Jun 8, 2010 13:12:12 GMT -8
I have also seen previously owned flatbed Railroad cars used as a bridge. These are of the correct width/ Length & more than enough weight carrying capacity to meet the requirements. The heavy loads & "span" engineering have already been done & the cars are available on the used market. These make great off-road bridges like the one needed for this DNR project! Can the DNR buy off on ( agree) to use a bridge like this? Transport to job site? Via the trail system?. I also know of at least one bridge like this that was transported by a heavy lift helicopter directly to job site & positioned in place. Costs? SEE RESEARCH & DESIGN REVIEW FOR USE OF RAILCARS FOR LOW VOLUME/ LOW COST ROAD BRIDGES (BELOW). www.iowadot.gov/operationsresearch/reports/reports_pdf/hr_and_tr/reports/tr421.pdfToyrocs Railcars are one of the things I was going to mention. They have always worked great from what I've seen!
|
|